Silver Blaze

Sherlock Holmes takes a vacation and visits his old friend Sir Henry Baskerville. His vacation ends when he suddenly finds himself in the middle of a double-murder mystery. Now he's got to find Professor Moriarty and the horse Silver Blaze before the great cup final horse race.
Inspector Gregory is one of the more competent police detectives Holmes works with in the course of the stories. He conducts a thorough investigation of the crime before Holmes' arrival, and gathers all the evidence Holmes needs to solve the case. Holmes notes that Gregory is "an extremely good officer," and claims that the only quality he lacks is imagination — being able to imagine what might have happened on a given occasion and act on this intuition.